1. Field of the Invention
The present invention relates to an optical transceiver, in particular, the invention relates to a pluggable optical transceiver.
2. Related Background Arts
An optical transceiver applicable to the optical communication system generally includes a transmitter optical subassembly (hereafter denoted as TOSA), a receiver optical subassembly (hereafter denoted as ROSA), and a circuit mounted on a circuit board to communicate with those optical subassemblies and the host system. These elements are enclosed within a housing. The pluggable optical transceiver is inserted within a cage prepared in the host system, where the cage installs an electrical connecter to receive an electrical plug mounted on the circuit board in the optical transceiver; thus, the optical transceiver may electrically communicate with the host system.
The TOSA and the ROSA mount respective optical devices, for instance, the TOSA may mount an laser diode (hereafter denoted as LD) to emit signal light, while, the ROSA may mount a photodiode (hereafter denoted as PD) to receive another signal light. These TOSA and ROSA are coupled with the circuit board through respective flexible printed circuit board (hereafter denoted as FPC). Recent requests for an optical transceiver make them faster in an operating speed and further intelligent in a function thereof. Accordingly, the circuit installed in the optical transceiver becomes further complex and larger, which becomes hard to install the circuit on a single circuit board. Some conventional optical transceivers, such as disclosed in the United States patent, U.S. Pat. No. 7,416,353, mount two circuit boards.